/*
 * This file is part of Mixin, licensed under the MIT License (MIT).
 *
 * Copyright (c) SpongePowered <https://www.spongepowered.org>
 * Copyright (c) contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package org.spongepowered.asm.util;

/**
 * Re-entrance semaphore used to share re-entrance data with the TreeInfo
 */
public class ReEntranceLock {
    
    /**
     * Max valid depth
     */
    private final int maxDepth;
    
    /**
     * Re-entrance depth
     */
    private int depth = 0;
    
    /**
     * Semaphore set when check exceeds a depth of 1
     */
    private boolean semaphore = false;
    
    public ReEntranceLock(int maxDepth) {
        this.maxDepth = maxDepth;
    }
    
    /**
     * Get max depth
     */
    public int getMaxDepth() {
        return this.maxDepth;
    }
    
    /**
     * Get current depth
     */
    public int getDepth() {
        return this.depth;
    }
    
    /**
     * Increase the re-entrance depth counter and set the semaphore if depth
     * exceeds max depth
     * 
     * @return fluent interface
     */
    public ReEntranceLock push() {
        this.depth++;
        this.checkAndSet();
        return this;
    }
    
    /**
     * Decrease the re-entrance depth
     * 
     * @return fluent interface
     */
    public ReEntranceLock pop() {
        if (this.depth == 0) {
            throw new IllegalStateException("ReEntranceLock pop() with zero depth");
        }
        
        this.depth--;
        return this;
    }
    
    /**
     * Run the depth check but do not set the semaphore
     * 
     * @return true if depth has exceeded max
     */
    public boolean check() {
        return this.depth > this.maxDepth;
    }
    
    /**
     * Run the depth check and set the semaphore if depth is exceeded
     * 
     * @return true if semaphore is set
     */
    public boolean checkAndSet() {
        return this.semaphore |= this.check();
    }
    
    /**
     * Set the semaphore
     * 
     * @return fluent interface
     */
    public ReEntranceLock set() {
        this.semaphore = true;
        return this;
    }
    
    /**
     * Get whether the semaphore is set
     */
    public boolean isSet() {
        return this.semaphore;
    }
    
    /**
     * Clear the semaphore
     * 
     * @return fluent interface
     */
    public ReEntranceLock clear() {
        this.semaphore = false;
        return this;
    }

}
